Stepmotor



July 17, 1934.

M. A. V. VAN DEN EYNDE STEPMOTOR Filed Jan. 14, 1953 MQW AT TO RNEY Patented July 17, 1934 PATENT OFFICE STEPMOTOR Maurice Auguste Victor Van den Eynde, Brussels, Belgium Application January 14, 1933, Serial No. 651,736

11 Claims.

This invention relates to a motor adapted to be used in several applications to move a given element or body by a step by step motion, for instance to move an index along a scale, or to operate a signalling dial or other apparatuses which must be brought in a given position.

The main object of my invention is to provide such a motor, (which will be hereinafter called shortly a stepmotor), which will be adapted to perform a correct and accurate step by step rotating motion in either direction that is to say either in clockwise or in anticlockwise direction.

With this object in view my invention essentially consists in the special combinations and arrangement of parts as will be hereinafter fully described and pointed out in the appended claims.

Referring to the annexed drawing which shows diagrammatically as an example one embodiment of my invention:

1 is a shaft adapted to be rotated in suitable bearings 2. On the said shaft is mounted a motion transmitting mechanism comprising for instance a worm 3 actuating a worm wheel 4 on the axis of which is mounted a hand or index 5 cooperating with a dial 6.

On a shaft 39 arranged in alignment with the shaft l, is keyed the rotor of an electromtor 7 adapted to be rotated in both directions under the influence of the electric current which is fed through a conductor 8 coming from a commutator 9 cooperating with three contacts i0-1l-12, two of which 11 and 12 are respec tively connected to the positive pole 13 and to the negative pole 14 of two electrical batteries 15 and 16, the second pole of which is put to the earth at 17 and 18 respectively.

In the conductor, between this commutator 9 and the electromotor 7, an electromagnet 19 of a polarized relay is inserted. This electromagnet is provided with a polarized armature 20 acting on a commutating lever 21 cooperating with three contacts 22-23 and 24. The commutating lever 21 is connected at its pivoting end 25 with one pole of a battery 26, the second pole of which is also connected to the earth at 18. The two contacts 23 and 24 are connected to a conductor 27 leading to the moving part 28 of a motion breaker comprising an electromagnet 29, the armature 30 of which carries a contact breaker 31 which is electrically connected to the conductor 27 and which is normally maintained in contact with a terminal plate 32 to which one end of the winding of the electromagnet 29 is connected, the second end of this winding being connected to the earth at 33 through a conductor 34. The armature 30 of the electromagnet 29 is subjected to the action of a spring 35 whichv tends to maintain the contact breaker 31 in contact with the plate 32 in such a manner that, 60 when this is the case and supposing the commutating lever 21 resting on one of the contacts 23 or 24, the current coming from the battery 26 is caused to pass through the winding of the electromagnet 29 which is then energized.

The armature 30 is provided with a latch 36 which is normally maintained, through the pressure of the spring 35, in contact with the periphery of a grooved disc 37 provided with a number of notches 38 in which the said latch is 70 adapted to be engaged when one of the saidnotches passes in front of the latch. This disc 37 is keyed on the shaft 1 which is connected to the shaft 39 of the electromotor 7 through an elastic driving device 40 comprising a disc 41 75 keyed on the shaft 1 and a, disc 42 keyed on the shaft 39. Both discs are provided with projecting pins 43 and 44 which are connected to each other by means of elastic bands or rubber rings 45.

In the example shown, the current which is fed to the electromotor 7, after having passed through this motor passes to the earth at 46 through a conductor 47. The stepmotor just described works as follows:

Suppose that a step by step motion must be transmitted by the stepmotor in a clockwise direction to the index 5 in front of the divisions 48 of the dial 6. The commutator 9 which, when the device is at rest, is normally placed on the dead 90 contact 10 is brought for instance on the contact 11. The current coming from the positive pole 13 of battery 15 passes then through the Winding of electromagnet 19 and is fed to the electromotor 7, returning to the second pole of the battery 95 through conductor 47 and the earth 46. As a consequence of the energizing of the electromagnet 19 the commutating lever 21 which was resting on the dead contact 22 is automatically brought on the contact 24 thus closing a circuit 100 for the release magnet 29 over a path extending from the negative pole of the battery 26, by way of the conductor 27, the contact breaker 31, plate 32, through the windings of the release magnet 29 and then through the conductor 34 and the 105 earth 33 to the positive pole of the battery 26. Simultaneously a permanent torque is exerted by the electromotor 7 on shaft 1, through the elastic bands of the elastic driving device 46 which are put under tension. The rotation of the said 110 shaft is however prevented in view of the fact that the latch 36 carried by the armature 30 of the electromagnet 29 is then engaged in one of the notches 38 of the disc 37. But at the same moment, the electromagnet 29 being now energized as above described, the armature 30 is attracted into the electromagnet 29 thus causing the latch 36 to release the disc 37 and simultaneously the contact breaker 31 to be carried a certain distance apart from the plate 32 thus interrupting the passage of the current in the winding of the electromagnet 29. The shaft 1 may then be rotated through the electromotor 7. But as, on account of the de-energizing of the electromagnet 29 the armature 30 together with the latch 36 is subjected to the pressure of the springs 35, this rotation can only take place until the latch 36 falls in the following notch 38 of disc 37, preventing again the rotation of the said disc and consequently of the shaft l, which however remains subjected to the permanent torque exerted by the electromotor 7. But the engagement of the latch 36 in the following notch of the disc 37 has for a result to bring again the contact breaker 31 in contact with the plate 32 thus closing again the circuit of the battery 26 through electromagnet 29 in such a manner that the armature 30 being again displaced in the electromagnet 29, again releases the disc 37 which then eiects a new partial rotation together with the shaft 1 under the permanent torque exerted on the said shaft by the electromotor 7. The same operation takes place automatically so long as the commutator 9 rests upon the contact 11 in such a manner that the shaft 1 and consequently the index 5 are rotated step by step in the same direction, the value of each step being in dependency on the number of notches 38 of the disc 37, the said disc acting consequently as steps-generating and measuring means. In the example shown the step by step motions are supposed to be used to displace the index 5 in front of the divisions of the dial 6 for instance in Olympic games to warn the public about items and results of Olympic games and the like, but it will be obvious that similar step by step motions could be used in a great number of applications each time it is wished to displace a body or other element by a succession of determined motions so as to bring the said body in a given position.

In order to cause the said body or element to be displaced similarly in the reversed direction, it is only necessary to displace the commutator 9 so as to bring it to rest upon the second operative contact 12. This contact being connected to the negative pole 14 of battery 16, the current is then reversed in the electromotor 7 whilst, on the other part, the polarized armature 20 of the electromagnet 19 is repulsed so as to bring the commutator lever 2l on the contact 23. The electromotor 7 being then subjected to a permanent torque in opposite direction the shaft 1 will be successively rotated partially in the reversed direction through the cooperation of the disc 37 with the electrically operated releasing means 29-30-36-31-32 It will be observed that in the above-described stepmotor the rotary motion effected under the action of a permanent torque is correctly divided into equal fractions or steps, each step having the same clockwise or anticlockwise direction as the permanent torque and corresponding to one instantaneous 'current passing through the releasing circuit 18-26-21--27-31-29-34-33--18- Moreover it will be noted that the just alluded to regularity of the step by step motion is partly .secured through the action of the elastic driving devi Ve 40, the second function of which is obviously to deaden the impacts whenever the shaft 1 and the disc 37 are stopped by latch 35.

That regulating action of the elastic driving 40 plays an important part when to and fro movements are imparted Vtothe index or other similar element in a more or less close succession and when consequently the reversal of the motion of the electromotor 7 might now and then take place whilst the disc 37 is still rotating in the other direction, that is to say, before the next notch 38 has reached the latch 36. In such a case, indeed, owing to the presence of the elastic driving device, the disc 37 will be able to complete its partial rotation through its own inertia, whilst the rubber rings 45 are first released from any tension and then put under tension in the other direction. In this way, the disc 37 and the index or other similar element mechanically connected to it will always accomplish a complete step, whenever the mechanism is released by an instantaneous current passing through the circuit 18--31-33 and will not move otherwise. Thus will be insured the perfect regularity of the step by step motion in either direction which is one object of the invention. It will be observed that in the above described arrangement the polarized relay 19-20 and the switch 21-22-23 are for the purpose of interrupting the releasing circuit 18-26-25--21-27-31--32-29-34--33- 18 when the stepmotor is at rest and to avoid a continuous hammering of armature 30 which would otherwise take place, should the battery 26 be connected directly to the conductor 27.

In the stepmotor as far as described, the successive steps would always be equal to one another. In practice however, it is necessary to suit the several applications, that the said steps may be made at will bigger or smaller. This result is secured by the cooperation with the stepsmeasuring disc 37, of steps-changing means consisting in the example shown in a change speed gear shown diagrammatically at 49 and inserted in the shaft 1 between the disc 37 and the transmitting mechanism 3 4. Such steps-changing means could be employed, for instance, when the same stepmotor must be used to produce different kinds of signals, each step corresponding, as an example, to one division of the dial 6 in a first instance and to 2 or more divisions of this dial in a second instance and so on.

In the example shown the reversible permanent torque is produced by driving means consisting of an electromator 7 fed either with positive or with negative current flowing from commutator 9.

What I claim is:

1. In a step by step motor, in combination with an element to be moved step by step in a direction or in the opposite one by the said motor, a shaft actuating said element, a motion transmitting mechanism inserted between the said shaft and the element which is to be acted upon, driving means whereby the shaft is subjected to a permanent torque, an elastic driving device inserted between the shaft and the driving means for said shaft, mechanical means adapted to stop periodically the rotation of the shaft whereby the generated steps are measured, releasing means cooperating with the said mechanical means to secure a step by step rotary motion of the shaft steps changing means coperating with the said mechanical stopping and releasing means and means whereby the permanent torque exerted on the shaft may be reversed or suppressed whereby bigger or smaller though always equal to one another fractions of motions in either direction may be imparted to the element.

2. In a step by step motor, in combination with an element to be moved step by step in a direction or in the opposite one by the said motor, a shaft actuating said element, a motion transmitting mechanism inserted between the said shaft and the element which is to be acted upon, an eleotromotor by which, when it is ted with electric current a permanent torque is exerted on the shaft in an either clockwise or anticlockwise direction and, when it is not fed with current no torque is exerted on the shaft, mechanical means adapted. to stop the shaft periodically, whereby the generated steps are measured, releasing means cooperating with the said mechanical means to cause rotary step by step motions of the shaft a change speed gear cooperating with the mechanical stopping means to vary the value of the generated steps, an elastic driving device inserted between the shaft and the electromotor and means to switch in or out or to reverse the current, thus causing the electromotor to revolve one Way or the other or to stop, whereby successive at will bigger or smaller though always equai to one another fractions of motion in either di rection may be imparted to the element.

3. in a step by step motor, in combination with an element to be moved step by step in a dire"- tion or in ie opposite one by the said motor, a shaft actuating said eiement, a motion transmitting mechanism inserted between the said sh and the element which is to be acted upon, an eiectroino'tor by which, when it is fed. with elec tric current, a permanent torque is exerted on the shaft, a keyed on the said shaft, the said. disc beine' provided on its periphery with a pluraiity of notches whereby the value or the generated steps determined and exactly lineasu pred, s, spring pressed. iatcifi adapted to engage the said notches to stop the rotation of the periodicaiiv, an electromagnet cooperating with. the spring ssed iatcn to release the disc periodically a, n the electrornotor is under cur-a a change speed gear cooperating with the notched to vary the vaine of the generated steps, an eiastic driving device inserted between the shaft the electro rotor and switching means to reverse the direc oi rotation of the electr-ernster cr to stop the said rotation.

s. in com ation, a shaft, electric driving means whereby the said shaft E subjected to permanent torque, mechanical means adapted to stop the shaft revolving under the action of the electric driving a polarized relay, releas ing means operated by the said relay and com operating with the said stopping mechanical means and switching means adapted to reverse the direction of rotation of the electric driving means.

in a step by step motor, in combination with an indicating dial, hand pointing at the dial compartments and to be moved step by step in an, either clockwise or anticiockwise direction, a shaft actuating said hand, a motion transmitting mechanism inserted between said shaft and said. hand, a change speed gear cooperating with the said transmitting mechanism, driving means whereby the said shaft is subjected to a permau1 nent torque, mechanical nieans'adapted to stop the shaft periodically, an elastic driving device inserted between the shaft and the said driving means, releasing means cooperating with the said mechanical means to secure a step by step rotary motion of the shaft and means whereby the permanent torque exerted on the shaft may be reversed or suppressed, whereby successive, at will bigger or smaller though always equal to one another fractions of motion in either direction may be imparted to the indicating or signallirug,r hand.

6. In a step by step motor, in combination with an element to be moved step by step in a direction or in the opposite one by the said motor, a shaft actuating said element, a motion transmitting mechanism inserted between the said. shaft and the element which is to be acted upon, a continuous current motor actuating said shaft by which, when it is fed with current, a permanent torque is exerted on the shaft in a direction, when it is fed with reversed current a permanent torque is exerted on the shaft in the reverse drection and when it is not fed with any current,`

no torque is exerted on the shaft, mechanicai means adapted to stop the shaft periodically, rcleasing means cooperating with the said rneclfianm ical means to cause rotary step by step motions of the shaft, a change speed gear cooperating with the mechanical stopping and releasing means to vary the value of the generated steps, an elastic drivingdevice inserted. between the shaft and the electromotor and means to switch in or out or to reverse the current, whereby sus cessive, at wili bigger or smaller though always equal to one another fractions of motion in either direction may be imparted to the element 7. In a step by step motor, in combination with an element to be moved step by step in a ciockwise or anticlocirwise direction. by the said. motor, a shaft actuating said element, a motion transmitting mechanism inserted between said shaft and the element which. is to be acted upon, an eiectrornotor by which, when it is Eef; with electric current, a permanent torque is en erted on the shaft in an either clockwise or antin clockwise direction and when it is fed with no current, no torque is exerted on. the snai chanical means adapted to arrest the sh riodicaliy, releasing means cooperating with the said mechanical means to cause rotary step by step motions or the shaft whereby steps or a predetermined value are generated, a change speed gear cooperating with the said mechanical stopping and releasing means to vary the value of the generated steps, an elastic driving device inserted between the shaft and the electromotor and a commutator which acts to feed electrically the motor or to deprive it ci any current, thus causing the stepmotor to revolve one way or the other or to stop and the element to move step by step accordingiff".

d. In a stepmotor, in combination, a iirst shaft, driving means whereby the said shaft is subjected to a permanent torque, a second shat, a yielding driving connection inserted between said shafts, steps generating and measuring means whereby the second shaft can be stopped mechanically and periodically and its motion thus divided into mathematically equal steps, releasing means cooperating with the said. steps generating and measuring means, means whereby the said releasing means are electrically operated only after each stopping of the second shaft and controlling means whereby the said driving means can apply, reverse or suppress their permanent torque, whereby a step by step motor is secured adapted to generate an accurate step by step motion in either direction or to be stopped according to needs.

9. In a stepmotor, in combination, a rst shaft, electrically operated driving means whereby the Said shaft is subjected to a permanent torque, a second shaft, a yielding driving connection inserted between said shafts, steps generating and measuring means whereby the second shaft can be stopped mechanically and periodically and its motion thus divided into mathematically equal steps, releasing means cooperating with the said steps generating and measuring means, means whereby the said releasing means are operated only after each stopping of the second shaft and switching means whereby the said electrically operated driving means can apply, reverse or suppress their permanent torque, whereby a step by step motor is secured adapted to generate an accurate step by step motion in either direction or to be stopped according to needs.

10. I n a stepmotor, in combination, a iirst shaft, electric driving means, whereby the said shaft is subjected to a permanent torque, a second shaft, a yielding driving connection inserted r between said shafts, steps generating and measuring means whereby the second shaft can be stopped mechanically and periodically and its motion thus divided into mathematically equal steps, releasing means cooperating with the said steps generating and measuring means, means whereby the said releasing means are operated only after each stopping of the second shaft and switching means whereby the said electric driving means can apply, reverse or suppress their permanent torque, whereby a step by step motor is secured adapted to generate an accurate step by step motion in either direction or to be stopped according to needs.

11. In a step motor, a first shaft, driving means whereby the said shaft is subjected to a permanent torque, a. second shaft, a yielding driving connection inserted between said shafts, steps generating and measuring means whereby the second shaft can be stopped mechanically and periodically and its motion thus divided into mathematically equal steps, releasing means cooperating with the said steps generating and measuring means, means whereby the said releasing means are electrically operated after each kstopping of the second shaft, controlling means whereby the said permanent torque may be applied, reversed or suppressed and switching means, actuated by the said controlling means, whereby the releasing means, are automatically brought in or out of action, by which combination of means a step motor is secured adapted to generate an accurate step by step motion in either direction or to be stopped according to needs.

MAURICE AUGUSTE VICTOR VAN DEN EYNDE. 

